In some of techniques of the past to detect the condition of a vehicle driver, the driving load on a driver is detected by the biological reactions of the driver, as disclosed in JP 264687/2002A, for example. Such biological reactions include heart beat, breath, electrodermal potential, and the like. In the technique disclosed in JP 219968/2002A, how a driver is looking off is detected from the orientation of the driver's face and how a drive is dozing is detected from the driver's opening/closing his/her eyes. In the technique disclosed in U.S. Pat. No. 5,642,093 (JP 203000/1996A), the presence/absence of a psychological stimulus that makes a psychological burden on or a visual stimulus to a driver is determined; and the wakefulness of the driver is detected by the presence/absence of this psychological stimulus. For example, the psychological burden comes from: the magnitude of the lane width and the degree of change in curvature radius of a road lying ahead of a subject vehicle that meets the driver's eyes; the presence/absence of a preceding vehicle, parked vehicle, or moving obstacle; or the presence/absence of the possibility of a rear-end collision with a preceding vehicle.
The driving condition of a driver unstable for driving includes such driving condition as inattentive driving, including “absent-minded driving and distracted driving,” as well as the above drowsy driving and driving without keeping the driver's eyes on the road ahead. These driving conditions of the driver need be considered.
When a driver drives a car, he/she repeatedly carries out three processes: the driver mainly visually acquires information required for traveling, and perceives the condition of traveling based on the acquired information (perception process); he/she determines a driving operation to travel in safety according to the perceived condition of traveling (determination process); and he/she performs the determined driving operation (action process). In cases where the driver does not appropriately perform any one process, he/she cannot continue safe traveling.
Therefore, the driving condition of a driver can be comprehensively determined by detecting the driving condition of the driver in the determination process and the operation process as well as in the perception process. The above conventional techniques are all for detecting whether the perception process can be appropriately carried out or not, and cannot detect the driving condition of a driver in the individual processes including the above three processes. Further, they are incapable of comprehensively determining the driving condition of a driver and providing alarms and driving assistance based on the determination.